Madonna is having second thoughts about signing up to perform at the Super Bowl - because she fears she has taken on too much for the beginning of 2012.The pop superstar confirmed she'd be playing the half-time show at the American football final earlier this month (Dec11) but with her directorial debut W.E. to promote, she worries that she'll be losing a lot of sleep. She says, "I was really torn about doing Super Bowl because I thought, 'Oh God, how can I do that and promote my film at the same time. It's a little bit much.' But my manager talked me into it and I'm still punishing him for that."